If you notice the caption on the bottom of the picture of the A2 at the top of the paper, there is mention of the A2 being introduced at .25 Cd .
This number is often given as the official Cd in published literature ( I've also seen .27 )
This makes me wonder what would have caused such a drastic rise in drag to .288 .

The only visible changes are the style of wheels, and surely this would only account for a count or two .

( And it also makes me wonder if they did the same mods to the .25 version, just how low of a Cd they would have achieved ! )

there is mention of the A2 being introduced at .25 Cd .
This number is often given as the official Cd in published literature ( I've also seen .27 )
This makes me wonder what would have caused such a drastic rise in drag to .288 .

The A2 was available in several different trim levels/models , one of which was a high-efficiency version ("3 L" diesel). That's what the .25 figure refers to. It had a different grille, wheels, tires (size) and partial underbody panels (if memory serves), and possibly also a lower ride height.

The A2 was available in several different trim levels/models , one of which was a high-efficiency version ("3 L" diesel). That's what the .25 figure refers to. It had a different grille, wheels, tires (size) and partial underbody panels (if memory serves), and possibly also a lower ride height.